X-ray tube.



PATENTED MAY 26, 1903.

,HEINZE, an. X-RAY TUBE.

APPLIOATXON FILED MAR. 19, 1903.

muoqm.

I i i UNITED STATES PATENT (D FICE.

TUBE.

SPECIFICATION forming part of Letters Patent N 0. 729,166, dated May 26, 1903. Application filed Math s, 1903. Serial No. 148.54g. (No mat-1) To all whom, it may concern:

Be it known that I, JOHN OTTo HEINzE, Jr. a citizen of the United States, residing at Chelsea, in the county of Sufiolk and State of Massachusetts, have invented certain new and useful Improvements in X-Ray Tubes, of which the following is a specification My invention relates to X-ray photography generally, but to X-ray or Crookes tubes particularly; and its. principal object is to provide means whereby the area of bombardment resulting from the play of the cathodestream on an anode of an X-ray tube is fixed both as to size and position on said anode, the details of the radiograph not being blurred, but sharp and clear, when said area of bombardment occupies a fixed position upon said i r anode and has the smallest possible diameter.

focal center and moves in a resulting curve ending at the anode. During the use of said tube the number of particles of gas in the tube that enter into circulation to form the cathode-stream varies and depends upon the relative individual charges of the particles or the amount of electric current sent through the tube, and thus determines the volume and diameter of the cathodestream. These variations in the cathode-stream cause the variations in the size and position of the area of bombardment on the anode. It is these changes in said area of bombardment that affect the clearness of definition of the body radiographed on a photographic plate, said body and said plate being in fixed positions relatively to the anode.

Now it is the object of my invention to provide means whereby I can so control said cathode-stream that it has an area of borrz ardment of the smallest possible diameter and having a fixed position on said anode.

In thedrawing illustrating the principle of 'my invention and the best known way now known to me of embodying said principle, A is an X-ray tube; B, its anode; 0, its cathode; c, the focal'center of said cathode, and D afunnel, preferably of metal, such as platinum.

E is a cathode-stream, ,While 0001; are any two particles of gas in said stream moving in paths 'y y from the cathode to the anode.

The funnel D lies between the cathode G iatented May 26,190 3f and anode B and is insulated therefrom. It I is heldin position bya support d, mounted in a glass supporting-arm a, blown into the tube. The longitudinalaxis of said funnel coincides with the axis of the cathode and anode. The inlet-orifice. of saidfunnel is adjacent to the cathode and is of suflicientsize to allow the whole of the cathode-stream E to flow into it freely, and its small discharge-orifice is in close proximity to the anode B. p

F, the object to be radiographed, is shown as a hand resting upon a photographic negative G.

The operation isas follows: An electric current is caused in the well-known manner to passt'rom the positive anode B to the cathode C, which immediately becomes negative. The gas particles, as a; w, in contact with the cathode becomev negative and are driven to ward the focal center a; but as they are negative they repel each other, and hence their result-ant directions are in curved paths 'y y, leading toward the anode B. These particles, with all that join to form the cathodestream E, enter the large orifice of the funnel D. The latter being metal, it becomes negatively charged by the bombardment of its walls by some of the moving negative particles and remains so charged during the flow of the cathode-stream.

As the funnel is negatively charged, it tends to drive away from it the negative particles, and with its converging interior surface thus concentrates said cathode-stream more and more, so that when the latter leaves the out- 100 let-orifice and strikes the positive anode atb it is of very small diameter. The area of bombardment lb is therefore very small, and :1 fnnn; D and the anode B are in fixer positions the area of bombardment is fixed.

The area ofi bombardment being small andconstant, and said area, the object F to be radiographed, and the photographic negative 5 G all being 'in positions fixed relatively to each other, the details of the object F will be sharply defined upon the negative F, and all the objections arising from an area of bombardment that varies either in diameter. IO or in its position upon the anode, or in both,

will beobviated and the objects of the invention obtained.

The funnel D may be made of metal. I prefer platinum, however, for the reason that I 5 it is hard and is less affected by the bombardment by some of the particles of the oathode-stream, which bombardment raises the temperature of the funnel to a very high degree. Glass cannot be used, for not being 20 charged electrically the particles freely beat against its walls and soon fuse it.

Having described my invention, and desiring to claim the same in thebroadest man -ner legally possible, what I claim is- JOHN OTTO HEINZE, JR.

Witnesses:

JOSEPH Gonson, L. S. RUSSELL. 

